ICO is a format (full name - Icon File) of bitmap images and refers to system files. Developed by Microsoft and designed to store icons in its operating system. ICO files, as a rule, store icon images - modest in size, with a small resolution (from 16x16 to 64x64 pixels), with different color depths (from 16 colors). In the graphical interface of various operating systems, ICO format files are used to display files, programs and folders (primarily in Windows) or as an icon for a specific website.
EMF is a vector graphics file for Windows operating system applications. Most image editing applications recognize it. The format was developed in 2007 by Microsoft. This is an integral part of Windows and a version of the original Windows Metafile Format (WMF), extended and expanded. It only supports 16-bit data. Image color data is stored in RGB format. There is no support for CMYK data. EMF (i.e. Enhanced Windows Metafile) can be used as a graphical language for printer drivers. It is used, in particular, to store collections of graphic images of Microsoft Clip Gallery. WMF also found application when it is necessary to transfer information through the clipboard (clipboard). From the Windows operating system, writing and reading to a file of this format can be carried out quickly and without problems. An EMF file is opened using a variety of utilities. For this, for example, IrfanView, CorelDRAW, Inkscape and GIMP are suitable. EMF files, like WMF, have a list of entries. Each of them is a specific team for drawing. Arguments that were 16-bit in WMF became 32-bit in EMF. EMF has features that introduce new arguments.